1. Technical Field
The invention relates to showing of a picture on a display, particularly to zooming in or out the picture with a touchscreen.
2. Related Art
Almost all smartphones and tablet computers are provided with a multi-touch screen. Such a multi-touch screen possesses a touch sensing surface's (trackpad or touchscreen) ability to recognize the presence of two or more points of contact with the surface. This plural-point awareness is often used to implement advanced functionality such as pinch to zoom or activating predefined programs. The pinch-to-zoom function is very useful in browsing pictures or web pages.
In recent years, some users prefer to connect their smartphones or tablets to a large-sized TV set or monitor for enlarging the picture. However, almost all TV sets and monitors are not provided with a touchscreen. Thus the pinch-to-zoom function cannot be performed on a TV set or monitor once a smartphone or tablet has been connected to the TV set or monitor. This will really cause inconvenience to users who are used to browse pictures of smartphones or tablets on a TV set.